DrJava is a lightweight programming environment for Java designed to foster test-driven software development. It includes an intelligent program editor, an interactions pane for evaluating program text, a source level debugger, and a unit testing tool.

The Lightweight Java Game Library (LWJGL) is a solution aimed directly at professional and amateur Java programmers alike to enable commercial quality games to be written in Java. LWJGL provides developers access to high performance crossplatform libraries such as OpenGL (Open Graphics Library), OpenCL (Open Computing Language) and OpenAL (Open Audio Library) allowing for state of the art 3D games and 3D sound. Additionally LWJGL provides access to controllers such as Gamepads, Steering wheel and Joysticks. All in a simple and straight forward API.
LWJGL is available under a BSD license, which means it's open source and freely available at no charge.

HSQLDB is a relational database engine written in Java, with a JDBC driver, conforming to ANSI SQL:2008. A small, fast, multithreaded engine and server with memory and disk tables, LOBs, transaction isolation, multiversion concurrency and ACID.

Importer library to import assets from different common 3D file formats such as Collada, Blend, Obj, X, 3DS, LWO, MD5, MD2, MD3, MDL, MS3D and a lot of other formats. The data is stored in an own in-memory data-format, which can be easily processed.
www.open3mod.com/ is a 3D model viewer and exporter based on Assimp that is also Open Source.

XDoclet is an extended Javadoc Doclet engine. It's a generic Java tool that lets you create custom Javadoc @tags and based on those @tags generate source code or other files (such as xml-ish deployment descriptors) using a template engine it provides.

SSVNC adds encryption security to VNC. It provides a GUI for Windows, MacOSX, and Unix that automatically starts up an SSL or SSH tunnel for connections to any VNC server. It also supports VeNCrypt encryption. The Unix viewer has many new features.

QuickFIX/J is an 100% Java implementation of the popular QuickFIX open source FIX protocol engine. QuickFIX/J features include support for FIX protocol versions 4.0 through 4.4 and 5.0/FIXT1.1 (www.fixprotocol.org).
Please note that the SourceForge SVN repo is read-only. Current repo can be found here: https://github.com/quickfix-j

The Lemur Project develops search engines, browser toolbars, text analysis tools, and data resources that support research and development of information retrieval and text mining software, including the Indri search engine and ClueWeb09 dataset.

PDFBox is a Java PDF Library. This project will allow access to all of the components in a PDF document. More PDF manipulation features will be added as the project matures. This ships with a utility to take a PDF document and output a text file.

CruiseControl is a framework for a continuous build process. It includes, but is not limited to, plugins for email notification, Ant, and various source control tools. A web interface is provided to view the details of the current and previous builds.